暗挖工程中洞内咬合桩止水帷幕技术研究

Study on Waterproof Wall Technology of Secant Pile in Underground Excavation Tunnel Engineering

以往咬合桩一般应用在地面敞开空间内,本文结合实际工程项目,对在地下暗挖工程的受限空间内实施洞内咬合桩进行了研究,重点对咬合桩的无筋桩材料、垂直度、咬合宽度、桩身局部受剪承载力等关键技术问题进行分析和优化。受到施工工艺限制,洞内咬合桩最终的垂直度只能控制在1%以内;无筋桩材料可采用低强度混凝土,能够满足桩身局部受剪承载力要求;对洞内咬合桩的实施效果进行了分析和评价;给出了咬合桩孔口加强和偏差过大处理的措施。

In the past,the secant pile was generally used in the ground open space.Combined with the actual engineering project,this paper makes a research on the implementation of the secant pile in the confined space of the underground excavation tunnel project,and focuses on the analysis and optimization of key technical problems such as the plain pile materials of secant pile,verticality,secant width and local shear bearing capacity of pile.Limited by construction technology,the final verticality of the secant pile in the tunnel can only be controlled within 1%;low strength concrete can be used for plain pile materials;the implementation effect of secant pile in the tunnel is analyzed and evaluated,and the treatment scheme for reinforcement and excessive deviation of secant pile is given.